Lens Moving Apparatus

ABSTRACT

A lens moving apparatus includes a bobbin adapted to move upward and downward in a first direction, a housing in which the bobbin is accommodated and which is movable upward and downward in the first direction, a cover member accommodating the bobbin and the housing, and a base to which a lower portion of the cover member is coupled, wherein the cover member has an opening formed in an upper face thereof, and is provided at an area thereof surrounding the opening with a first stopper for limiting a distance by which the bobbin moves upward.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. §119 to KoreanPatent Application No. 10-2014-0193764, filed on Dec. 30, 2014, andKorean Application No. 10-2015-0004071, filed on Jan. 12, 2015, whichare hereby incorporated by reference in their entirety.

TECHNICAL FIELD

Embodiments relate to a lens moving apparatus.

BACKGROUND

It is difficult to adopt voice coil motor (VCM) technology, which istypically used in conventional camera modules, for use in anultracompact camera module, which aims at achieving low powerconsumption, and thus research into the technology has been activelyundertaken.

A camera module mounted in a small-sized electronic product, such as asmart phone, may incorporate an autofocusing function of automaticallyfinding the optimal focus of a lens with respect to an object.

In addition, the camera module may minutely shake due to the tremblingof the user's hand while taking a photograph. Therefore, there is a highnecessity for a technology capable of incorporating a handshakecorrection function into the camera module.

In order to fulfill the autofocusing and handshake correction functionsof a lens, the camera module may incorporate a lens moving apparatus formoving a lens provided in the camera module upward and downward in thefirst direction and in the second and/or third direction, which areperpendicular to the first direction.

When a lens barrel in which one or multiple lenses constitute theoptical system is moved in the first, second or third direction by alens moving apparatus, the components provided in the camera module maycollide with each other, and the components may be damaged or broken dueto the collision.

For the purpose of precise and efficient autofocusing and handshakecorrection, there is a necessity to appropriately limit the distance bywhich a lens or a lens barrel moves in the first, second or thirddirection.

A conventional IT product incorporating an ultracompact digital camerais provided therein with a lens moving apparatus for fulfilling anautofocusing function of controlling the focal length of a lens byadjusting the distance between the lens and an image sensor forconverting external light into a digital image or a digital video.

Autofocusing may be implemented in such a way as to measure adisplacement value in the optical axis direction, that is, in the firstdirection, by means of a unit for detecting displacement in the opticalaxis direction, which is provided in the lens moving apparatus, andadjust the distance between the image sensor and the lens by means of acontroller based on the measured displacement value.

Accordingly, there is a high necessity for a lens moving apparatushaving a configuration capable of measuring a displacement value in thefirst direction and a camera module including the lens moving apparatus.

BRIEF SUMMARY

Accordingly, an object of the embodiments is to provide a lens movingapparatus capable of appropriately limiting the distance by which a lensor a lens barrel moves in the first, second or third direction.

Another object of the embodiments is to provide a lens moving apparatushaving a configuration capable of accurately measuring a displacementvalue in the first direction.

In one embodiment, a lens moving apparatus includes a bobbin adapted tomove upward and downward in a first direction, a housing in which thebobbin is accommodated and which is movable upward and downward in thefirst direction, a cover member accommodating the bobbin and thehousing, and a base to which a lower portion of the cover member iscoupled, wherein the cover member has an opening formed in an upper facethereof, and is provided at an area thereof surrounding the opening witha first stopper for limiting a distance by which the bobbin movesupward.

In another embodiment, a lens moving apparatus includes a bobbin adaptedto move upward and downward in a first direction, a housing in which thebobbin is accommodated and is movable upward and downward in the firstdirection, a cover member accommodating the bobbin and the housing, anda base to which a lower portion of the cover member is coupled, whereinthe bobbin includes a fifth stopper, which protrudes downward from alower portion of the bobbin to limit a distance by which the bobbinmoves downward in a second or third direction.

In a further embodiment, a lens moving apparatus includes a firstmagnet, a housing on which the first magnet is mounted, a bobbin on anouter surface of which a coil is wound, a second magnet mounted on thebobbin, and a position detection sensor disposed to face the secondmagnet, wherein the coil includes a plurality of coils, which are woundaround a plurality of areas of an outer surface of the bobbin and arespaced apart from each other in the first direction, and the positiondetection sensor is disposed at at least a portion thereof between theplurality of coils.

BRIEF DESCRIPTION OF THE DRAWINGS

Arrangements and embodiments may be described in detail with referenceto the following drawings in which like reference numerals refer to likeelements and wherein:

FIG. 1 is a perspective view showing a lens moving apparatus accordingto an embodiment of the present invention;

FIG. 2 is an exploded perspective view showing the lens moving apparatusaccording to the embodiment;

FIG. 3 is a cross-sectional view showing part of the lens movingapparatus according to the embodiment.

FIG. 4 is a perspective view showing a bobbin according to anembodiment;

FIG. 5 is a bottom perspective view showing the bobbin according to anembodiment;

FIG. 6 is a fragmentary perspective view showing part of the lens movingapparatus according to an embodiment;

FIG. 7 is a bottom perspective view showing a housing according to anembodiment;

FIG. 8 is a perspective view showing part of the lens moving apparatusaccording to the embodiment;

FIG. 9 is a side view showing part of the lens moving apparatusaccording to the embodiment;

FIG. 10 is an enlarged view showing region A of FIG. 9;

FIG. 11 is a perspective view schematically showing the lens movingapparatus according to another embodiment;

FIG. 12 is an exploded perspective view showing the lens movingapparatus according to the embodiment;

FIG. 13 is a perspective view showing the lens moving apparatusaccording to an embodiment, in which the coil is coupled to the bobbin;

FIG. 14A is a perspective view showing the lens moving apparatusaccording to an embodiment, in which the second magnet is coupled to thebobbin;

FIG. 14B is front view showing the magnetized structure of the secondmagnet according to an embodiment;

FIG. 14C is a front view showing the magnetized structure of the secondmagnet according to another embodiment;

FIG. 15 is a side view showing the disposition of the bobbin, theposition detection sensor and the second magnet in the lens movingapparatus according to an embodiment;

FIG. 16 is a side view showing the disposition of the bobbin, theposition detection sensor, the second magnet and the coils in the lensmoving apparatus according to the embodiment; and

FIG. 17 is a graph representing the results of experimentation on thedrive characteristics of the lens moving apparatus according to anembodiment.

DETAILED DESCRIPTION

Hereinafter, embodiments will be described with reference to theattached drawings. In the drawings, the same or similar elements aredenoted by the same reference numerals even when they are depicted indifferent drawings. In the following description, a detailed descriptionof known functions and configurations incorporated herein will beomitted when it may make the subject matter of the disclosure ratherunclear. Those skilled in the art will appreciate that some features inthe drawings are exaggerated, reduced, or simplified for ease indescription, and drawings and elements thereof are not shown always atthe proper proportion.

For reference, in the respective drawings, a rectangular coordinatesystem (x, y, z) may be used. In the drawings, the x-axis and the y-axismean a plane perpendicular to an optical axis and, for convenience, anoptical axis (z-axis) direction may be referred to as a first direction,an x-axis direction may be referred to as a second direction, and ay-axis direction may be referred to as a third direction.

FIG. 1 is a perspective view showing a lens moving apparatus accordingto an embodiment of the present invention. FIG. 2 is an explodedperspective view showing the lens moving apparatus according to theembodiment.

An handshake correction apparatus, which is applied to compact cameramodules of mobile devices such as smart phones or tablet PCs, refers toan apparatus configured to prevent the contour of an image, capturedwhen taking a still image, from being unclearly formed due to vibrationscaused by the trembling of the user's hand.

In addition, an autofocusing apparatus is configured to automaticallyfocus the subject image on the surface of an image sensor (not shown).The handshake correction apparatus and the autofocusing apparatus may beconfigured in various manners. In the embodiments, the lens movingapparatus may perform the handshake correction and/or autofocusingoperations in such a manner as to move an optical module, composed of aplurality of lenses, in a first direction or in a plane perpendicular tothe first direction.

As shown in FIGS. 1 and 2, the lens moving apparatus according to anembodiment may include a movable unit. The movable unit may fulfill thefunctions of autofocusing and handshake correction for a lens. Themovable unit may include a bobbin 110, a first coil 120, first magnets130, a housing 140, an upper elastic member 150 and a lower elasticmember 160.

The bobbin 110 may be accommodated in the housing 140. The first coil120, which is disposed in the first magnets 130, may be provided on theouter surface of the bobbin 110. The bobbin 110 may be mounted so as tobe reciprocated in a first direction in the internal space of thehousing 140 by electromagnetic interaction between the first magnets 130and the first coil 120. The first coil 120 may be provided on the outersurface of the bobbin 110 so as to electromagnetically interact with thefirst magnets 130.

The bobbin 110 may be moved in the first direction while beingelastically supported by the upper and lower elastic members 150 and160, thereby fulfilling the autofocusing function.

The bobbin 110 may include a lens barrel (not shown) into which at leastone lens is mounted. The lens barrel may be internally coupled to thebobbin 110 in various manners.

In an example, the bobbin 110 may be provided on the inner surfacethereof with a female threaded portion, and the lens barrel may beprovided on the outer surface thereof with a male threaded portioncorresponding to the female threaded portion, whereby the lens barrelmay be coupled to the bobbin 110 by means of threaded engagementtherebetween. However, the coupling between the lens barrel and thebobbin 110 is not limited thereto, and the lens barrel may be directlycoupled to the inside of the bobbin 110 in a way other than the threadedengagement, without providing the female threaded portion on the innersurface of the bobbin 110. Alternatively, one or more lenses may beintegrally formed with the bobbin 110 without using the lens barrel.

The lens, which is coupled to the lens barrel, may be composed of asingle lens, or two or more lenses constituting an optical system.

The autofocusing function may be controlled by changing the direction ofcurrent, or may be fulfilled by the action of moving the bobbin 110 inthe first direction. For example, the bobbin 110 may be moved upwardfrom its initial position upon the application of forward current, andmay be moved downward upon the application of reverse current. Thedistance by which the bobbin 110 moves in one direction from the initialposition may be increased or decreased by controlling the amount ofcurrent flowing in one direction.

The bobbin 110 may be provided on upper and lower surfaces thereof witha plurality of upper support protrusions and a plurality of lowersupport protrusions, respectively. The upper support protrusions may beconfigured to have a circular cylindrical shape or a rectangular columnshape, and may serve to couple or secure the upper elastic member 150thereto. The lower support protrusions may also be configured to have acircular cylindrical shape or a rectangular column shape, and may serveto couple or secure the lower elastic member 160 thereto, like the uppersupport protrusions.

The upper elastic member 150 may have through holes corresponding to theupper support protrusions, and the lower elastic member 160 may havethrough holes corresponding to the lower support protrusions. Therespective support protrusions and the corresponding through holes maybe fixedly coupled to each other by means of thermal fusion or anadhesive such as epoxy.

The housing 140 may be configured to have a hollow column, for example,an approximately rectangular hollow column capable of supporting thefirst magnets 130. Each lateral side of the housing 140 may be providedwith the first magnet 130 and support members 220 secured thereto. Asdescribed above, the bobbin 110 may be disposed on the inner surface ofthe housing 140, and may be guided and moved in the first direction bythe housing 140.

Each of the upper and lower elastic members 150 and 160 may be coupledto both the housing 140 and the bobbin 110, and the upper elastic member150 and the lower elastic member 160 may elastically support the upwardor downward movement of the bobbin 110 in the first direction. The upperelastic member 150 and the lower elastic member 160 may be constitutedby a leaf spring.

As shown in FIG. 2, the upper elastic member 150 may be composed of aplurality of elastic members, which are separated from each other. Byvirtue of the multiple partitioning structure, current having differentpolarities or different electric powers may be applied to the respectiveelastic members of the upper elastic member 150. The lower elasticmember 160 may also be composed of a plurality of elastic members, andmay be conductively connected to the upper elastic member 150.

The upper elastic member 150, the lower elastic member 160, the bobbin110 and the housing 140 may be assembled to one another by means ofthermal fusion and/or bonding using an adhesive or the like.

The base 210 may be disposed under the bobbin 110, and may be configuredto have an approximately rectangular shape. A printed circuit board 250may be mounted on the base 210.

The regions of the base 210 that face terminal members 253 of theprinted circuit board 250 may be provided with respective supportrecesses having a size corresponding to that of the terminal members253. The support recesses may be recessed from the outer circumferentialsurfaces of the base 210 by a predetermined depth such that the terminalmembers 253 do not protrude outward from the outer circumferentialsurface of the base 210 or such that the extent to which the terminalmembers 253 protrude can be controlled.

The support members 220 are disposed on the lateral sides of the housing140 such that the upper sides of the support members 220 are coupled tothe housing 140 and the lower sides of the support members 220 arecoupled to the base 210. The support members 220 may support the bobbin110 and the housing 140 in such a manner as to allow the bobbin 110 andthe housing 140 to move in the second and third directions,perpendicular to the first direction. The support members 220 may beconductively connected to the first coil 120.

Since the support members 220 according to the embodiment are disposedone on the outer surface of each corner of the housing 140, a total offour support members 220 may be disposed. The support members 220 may beconductively connected to the upper elastic member 150. Specifically,the support members 220 may be conductively connected to regions aroundthe through holes.

Since the support members 220 are made of a material different from thatof the upper elastic member 150, the support members 220 may beconductively connected to the upper elastic member 150 by means of aconductive adhesive, solder or the like. Consequently, the upper elasticmember 150 may apply current to the first coil 120 through the supportmembers 220 conductively connected thereto.

The support members 220 may be connected to the printed circuit board250 through the through holes formed in the circuit member 231 and theprinted circuit board 250. Alternatively, in place of forming thethrough holes in the circuit member 231 or the printed circuit board250, the support members 220 may be conductively soldered to the area ofthe circuit member 231 at which the through hole would be formed.

Although the support members 220 are illustrated in FIG. 2 as beingembodied as linear support members according to an embodiment, thesupport members 220 are not limited thereto. In other words, the supportmembers 220 may be configured to have a plate shape or the like.

Second coils 230 may move the housing 140 in the second and/or thirddirections to perform the handshake correction by virtue ofelectromagnetic interaction with the first magnets 130.

The second or third direction may include not only the x-axis directionor the y-axis direction but also a direction which is substantiallyclose to the x-axis direction or the y-axis direction. In other words,in terms of driving in the embodiments, although a housing 140 may movein a direction parallel to the x-axis or the y-axis, the housing maymove in a direction which is slightly inclined with respect to thex-axis or the y-axis in the state of being supported by a support member220.

Accordingly, the first magnets 130 are required to be disposed atpositions corresponding to the second coils 230.

The second coils 230 may be disposed so as to face the first magnets130, which are secured to the housing 140. In one embodiment, the secondcoils 230 may be disposed outside the first magnets 130, or may bedisposed under the first magnets 130 so as to be spaced apart from thefirst magnets 130 by a predetermined distance.

Although a total of four second coils 230 may be disposed one on eachside of a circuit member 231 according to the embodiment, the disclosureis not limited thereto. Only two second coils 230, that is, one secondcoil for movement in the second direction and one second coil formovement in the third direction, may be provided, or a total of morethan four second coils 230 may be provided.

In the embodiment, although circuit patterns having the shape of thesecond coils 230 are formed on the circuit member 231 and additionalsecond coils are disposed on the circuit member 231, the disclosure isnot limited thereto. Alternatively, only additional second coils 230 maybe disposed on the circuit member 231, without forming the circuitpatterns having the shape of the second coils 230.

Furthermore, the second coils 230, which have been prepared by windingwires into a doughnut shape or which have the shape of a finelypatterned coil, may be conductively connected to the printed circuitboard 250.

The circuit member 231 including the second coils 230 may be disposed onthe upper surface of the printed circuit board 250, which is positionedover the base 210. However, the disclosure is not limited thereto, andthe second coils 230 may be disposed on the base 210 in a state of beingin close contact therewith, or may be spaced apart from the base 210 bya predetermined distance. In other examples, a substrate on which thesecond coils are formed may be layered on the printed circuit board 250and connected thereto.

The printed circuit board 250 may be conductively connected to at leastone of the upper elastic member 150 and the lower elastic member 160,and may be coupled to the upper surface of the base 210. As shown inFIG. 2, the printed circuit board 250 may have through holes formed atpositions corresponding to the support members 220, so as to allow thesupport members 220 to be fitted into the through holes.

The printed circuit board 250 may be provided with the terminal members253, which are formed by bending portions of the printed circuit board250. Each terminal member 253 includes a plurality of terminals 251 forthe application of external power to the terminal members 253, wherebycurrent is supplied to the first coil 120 and the second coils 230. Thenumber of terminals 251 provided on each terminal member 253 may beincreased or decreased depending on the kinds of components to becontrolled. Alternatively, the number of terminal members 253 providedon the printed circuit board may be one, or three or more.

A cover member 300, which is configured to have an approximate boxshape, may accommodate the movable unit, the second coils 230 and aportion of the printed circuit board 250, and may be coupled to the base210. The cover member 300 may serve to protect the movable unit, thesecond coils 230, the printed circuit board 250 and the like,accommodated therein, from damage, and may serve to prevent anelectromagnetic field, which is generated by the first magnets 130, thefirst coil 120, the second coils 230 and the like, from leaking outward,thereby concentrating the electromagnetic field.

FIG. 1 is a perspective view showing the lens moving apparatus accordingto an embodiment. FIG. 3 is a cross-sectional view showing part of thelens moving apparatus according to the embodiment.

The lens moving apparatus according to the embodiment may include afirst stopper 410. As shown in FIGS. 1 and 3, the first stoppers 410 maybe formed on the cover member 300 in the first direction.

Specifically, the cover member 300 may be configured to have a box shapehaving an opening S formed in the upper wall thereof. The first stoppers410 may be positioned around the periphery of the opening S over thebobbin 110, and may limit the distance by which the bobbin 110 can moveupward.

The first stoppers 410 may include a plurality of stoppers, which arecircumferentially disposed around the periphery of the opening S atregular intervals. Here, the first stoppers 410 may be symmetricallydisposed around the opening S.

In order to limit the distance by which the bobbin 110 can be movedupward while keeping the bobbin 110 in the state of not being inclinedin the second or third direction, perpendicular to the first direction,the first stoppers 410 may be preferably disposed in a symmetricalarrangement, as described above.

The first stoppers 410 may be formed by depressing the outer surface ofthe upper wall of the cover member 300 to thus make the inner surface ofthe upper wall protrude. Alternatively, the first stoppers 410, havingthis configuration, may be formed by injection molding, rolling or thelike.

The first stoppers 410 may limit the distance by which the bobbin 110can move upward in the first direction. If the bobbin 110 moves upwardtoo far, it is difficult to easily and efficiently control the distancethat the bobbin 110 moves upward, and the upper elastic member 150 andthe lower elastic member 160 may be excessively deformed due to theexcessive displacement of the bobbin 110.

Accordingly, in order to prevent the drive characteristics and thereliability of products from being deteriorated for that reason, thedistance by which the bobbin 110 moves upward may be appropriatelyrestricted by providing the first stoppers 410 to the cover member 300.

The distance by which the bobbin 110 moves upward may be appropriatelyrestricted by contact between the lower ends of the first stoppers 410and the upper end of the bobbin 110. By appropriately setting thedistance by which the first stoppers 410 protrude downward in the firstdirection and the shape and height of the region of the bobbin 110 thatcontacts the first stoppers 410, the distance by which the bobbin 110moves upward may be appropriately restricted by the first stoppers 410.

The lens moving apparatus according to the embodiment may include secondstoppers 420. As shown in FIGS. 1 and 3, the second stopper 420 may beformed on the cover member 300. Specifically, the second stoppers 420may be formed near respective sides of the upper wall of the covermember 300.

The second stoppers 420 may be disposed to face the upper end of thehousing 140 so as to limit the distance by which the housing 140 movesupward. The second stoppers 420 may include a plurality of stoppers,which are symmetrically disposed around the opening S.

In order to limit the distance by which the housing 140 can move upwardwhile keeping the housing 140 in the state of not being inclined in thesecond or third direction, perpendicular to the first direction, thesecond stoppers 420 may be preferably disposed in the symmetricalarrangement described above.

The second stoppers 420 may be formed by depressing the outer surface ofthe upper wall of the cover member 300 downward to thus cause the innersurface of the upper wall to protrude downward. The second stoppers 420having this configuration may be formed by injection molding, rolling orthe like.

The second stoppers 420 may limit the distance by which the housing 140moves upward in the first direction. Unlike the bobbin 110, the housing140 may not actively move upward and downward in the first direction.

However, when the lens moving apparatus performs the handshakecorrection operation, the housing 140 may be inclined in the second orthird direction, whereby the housing may move upward in the firstdirection.

As the housing 140 moves upward, the support members 220 may be extendedin the length direction by being subjected to the tensile force orbending moment. Accordingly, when the excessive upward movement of thehousing 140 is repeated, the support members 220 are extended so farthat the deformation of the support members 220 exceeds the limit ofelasticity, whereby the support members 220 may be damaged, evenbreaking in severe cases.

Accordingly, in order to prevent damage, breakage or the like of thesupport members 220, there is a need to limit the upward movement of thehousing 140. The second stoppers 420 may limit the distance by which thehousing 140 moves upward in order to prevent damage, breakage or thelike of the support members 220.

By virtue of the limitation of the distance by the housing 140 movesupward, there is an effect of being able to easily control the resonancefrequency when mechanical resonance is generated from the supportmembers 220.

The distance by which the housing 140 moves upward may be limited bycontact between the lower end and upper end of the second stoppers 420.By appropriately setting the distance by which the second stoppers 420protrude downward in the first direction and the shape and height of theregion of the housing 140 that contacts the second stoppers 420, thedistance by which the housing 140 moves upward may be appropriatelyrestricted by the second stoppers 420.

The lens moving apparatus according to the embodiment may include thirdstoppers 430. As shown in FIGS. 1 and 3, the third stoppers 430 may beformed on the cover member 300. Specifically, the third stoppers 430 maybe formed on the side walls of the cover member 300 so as to limit thedistance by which the housing 140 can move in the second or thirddirection.

Since the bobbin 110 may be supported by the housing 140 and may move inthe second or third direction together with the housing 140, the thirdstoppers 430 may limit the distance by which the housing 140 moves inthe second or third direction, and may thus limit the distance by whichthe bobbin 110 moves in the second or third direction.

The third stoppers 430 may be disposed to face the side surfaces of thehousing 140 so as to serve to limit the distance by which the housing140 moves in the second or third direction. The third stoppers 430 mayinclude a plurality of stoppers, which are symmetrically disposed aroundthe opening S.

In order to allow the housing 140 to move in the second or thirddirection and make the distances that the housing moves 140 in thesecond and third directions uniform while the lens moving apparatusperforms the handshake correction operation, the third stoppers 430 maybe preferably disposed in the symmetrical fashion described above.

The third stoppers 430 may be formed by depressing the outer surfaces ofthe side walls of the cover member 300 inward and causing the innersurfaces of the side walls to protrude inward. Alternatively, the thirdstoppers 430 having this configuration may be formed by injectionmolding, rolling or the like.

The third stoppers 430 may be formed on planar parts of the side wallsof the cover member 300. In order to realize a structure that allows thethird stoppers 430 to be easily formed and allows the outer surfaces ofthe housing 140 to contact the third stoppers 430 while preventing theouter surfaces of the housing 140 and the third stoppers 430 frominterfering with other components or structures, it may be preferablethat the third stoppers 430 be formed on the planar parts of the sidewalls of the cover member 300.

In one embodiment, the third stoppers 430 may be disposed to face firstprotrusions 141 formed on side surfaces of the housing 140. In theembodiment, since a total of eight first protrusions 141 are formed twoon each planar part of the outer surfaces of the housing 140, a total ofeight third stoppers 430 may also be formed two on each planar part ofthe side walls of the cover member 300.

Since the third stoppers 430 are positioned to correspond to the firstprotrusions 141, the third stoppers 430 may be formed on the covermember 300 in a number and at positions corresponding to the number andpositions of the first protrusions 141.

When the third stoppers 430 are disposed at positions corresponding tothe first protrusions 141, it is possible to reduce the depth of thethird stoppers 430, and the first protrusions 141 may alleviate impactsand vibrations applied to the housing 140 upon collision between thefirst protrusions 141 and the third stoppers 430.

However, the disposition of the third stoppers 430 is not limitedthereto. For example, the third stoppers 430 may be disposed so as tocontact portions of the outer surface of the housing 140 at which thefirst protrusions 141 are not formed.

During the handshake correction operation of the lens moving apparatus,the housing 140 may move in the second or third direction, and thesupport members 220 may be extended in the length direction thereof bybeing subjected to a tensile force or bending moment caused by themovement of the housing 140.

When the excessive movement of the housing 140 in the second or thirddirection is repeated, the support members 220 are extended so far thatthe deformation of the support members 220 exceeds the elastic limit,whereby the support members 220 may be damaged and may be broken due tofatigue.

Accordingly, in order to prevent damage, breakage or the like of thesupport members 220, there is a need to limit the movement of thehousing 140 in the second and third directions. The third stoppers 430may limit the distance that the housing 140 moves in the second or thirddirection in order to suppress damage, breakage or the like of thesupport members 220. In addition, by virtue of the limitation of thedistance by which the housing 140 moves in the second or thirddirection, there is an effect of being able to easily control aresonance frequency when mechanical resonance is generated from thesupport members 220.

The distance by which the housing 140 moves in the second or thirddirection may be appropriately limited by contact between the outersurface of the housing 140 or the first protrusions 141 and the thirdstoppers 430.

By appropriately setting the distance that the third stoppers 430protrude inward from the cover member 300 and the shape and protrudingheight of the outer surface of the housing 140 or the first protrusions141, which contact the third stoppers 430, the distance by which thehousing 140 moves in the second or third direction may be appropriatelyrestricted by the third stoppers 430.

FIG. 3 is a cross-sectional view showing part of the lens movingapparatus according to an embodiment. FIG. 4 is a perspective viewshowing the bobbin 110 according to an embodiment.

The lens moving apparatus according to the embodiment may include fourthstoppers 440.

As shown in FIGS. 3 and 4, the fourth stoppers 440 may be formed on thebobbin 110. Specifically, the fourth stoppers 440 protrude from theouter surface of the bobbin 110 so as to limit the distance that thebobbin 110 can move downward. Each of the fourth stoppers 440 mayinclude a second protrusion 441 and a third protrusion 442.

The second protrusion 441 may be disposed such that the lower surfacethereof faces a first stepped portion 142, which is formed on thehousing 140 so as to limit the distance by which the bobbin 110 movesdownward. Accordingly, when the bobbin 110 moves downward in the firstdirection, the bobbin 110 may move downward by the distance between thesecond protrusion 441 and the first stepped portion 142 of the bobbin110.

The third protrusion 442 protrudes upward from the second protrusion 441and contacts part of the inner surface of the housing 140, therebyfunctioning to guide the movement of the bobbin 110 in the firstdirection together with the housing 140.

The second protrusions 441 may contact at least part of the innersurface of the housing 140 so as to guide the movement of the bobbin 110in the first direction. In other words, the second protrusions 441 andthe third protrusions 442 may collectively function to guide themovement of the bobbin 110 in the first direction.

The second protrusion 441 may be configured to have a larger surfacearea than the third protrusion 442 when viewed in the first direction.The second protrusion 441 may function to limit the distance by whichthe bobbin 110 moves downward and guide the movement of the bobbin 110in the first direction.

Accordingly, unlike the third protrusion 442, the second protrusion 441may contact the housing 140 at the lower surface and side surfacethereof. Accordingly, it may be preferable for the second protrusion 441to be designed to have a larger surface area than the third protrusion442 so as to resist impact and abrasion caused by the housing 140.

The fourth stoppers 440 may include a plurality of stoppers, and may besymmetrically disposed around the center of the bobbin 110. In order tolimit the distance by which the bobbin 110 can move downward whilekeeping the bobbin 110 in the state of not being inclined in the secondor third direction, perpendicular to the first direction, the fourthstoppers 440 may be preferably disposed in the symmetrical fashiondescribed above.

The fourth stoppers 440 may appropriately limit the distance by whichthe bobbin 110 moves downward by contact between the lower ends of thesecond protrusions 441 and the first stepped portions 142 of the housing140. Accordingly, the fourth stoppers 440 may function to prevent thebobbin 110 from moving too far downward and keep the distance by whichthe bobbin 110 moves downward within the intended range.

By appropriately designing the positions of the second protrusions 441of the fourth stoppers 440 on the bobbin 110 and the shapes of thesecond protrusions 441, the distance by which the bobbin 110 movesdownward may be appropriately limited by the fourth stoppers 440.

FIG. 5 is a bottom perspective view showing the bobbin 110 according toan embodiment. FIG. 6 is a fragmentary perspective view showing part ofthe lens moving apparatus according to an embodiment.

The lens moving apparatus according to the embodiment may include fifthstoppers 450.

As shown in FIGS. 5 and 6, the fifth stoppers 450 may be formed on thebobbin 110. Specifically, the fifth stoppers 450 may protrude downwardfrom the lower surface of the bobbin 110 so as to function to limit thedistance by which the bobbin 110 moves in the downward direction or inthe second or third direction.

Each of the fifth stoppers 450 may include a fifth protrusion 451 and asixth protrusion 452. The fifth protrusion 451 may be positioned suchthat a portion of the lower surface thereof faces the fourth protrusion211, which protrudes upward from the base 210. The fifth protrusion 451may contact the upper surface of the fourth protrusion 211 so as tolimit the distance by which the bobbin 110 moves downward in the firstdirection.

The sixth protrusion 452 protrudes downward from the fifth protrusion451, and a portion of the sixth protrusion 452 contacts the innersurface of the fourth protrusion 211 so as to limit the distance bywhich the bobbin 110 moves in the second or third direction.

The fourth protrusion 211 may protrude upward from the upper surface ofthe base 210. The upper surface of the fourth protrusion 211 may contactthe lower surface of the fifth protrusion 451 so as to limit thedistance by which the bobbin 110 moves downward. The inner surface ofthe fourth protrusion 211 may contact a portion of the side surface ofthe sixth protrusion 452 so as to limit the distance by which the bobbin110 moves in the second or third direction.

The fourth protrusion 211 may be configured to have any shape orstructure, as long as the fourth protrusion 211 can fulfill theabove-described function. For example, the fourth protrusion 211 may beconfigured to have a closed curve shape when viewed in the firstdirection, or may be configured to include discontinuous protrusionswhich protrude from the regions corresponding to the plurality of fifthstoppers 450.

The fifth protrusion 451 may be configured to have a larger surface areathan the sixth protrusion 452 when viewed in the first direction. Thearea of the lower surface of the fifth protrusion 451, excluding thearea at which the sixth protrusion 452 protrudes downward, may contactthe upper surface of the fourth protrusion 211 so as to limit thedistance by which the bobbin 110 moves downward. For this reason, thefifth protrusion 451 preferably has a larger surface area than the sixthprotrusion 452 when viewed in the first direction.

When the bobbin 110 moves too far downward, the lower end of the lensbarrel coupled to the bobbin 110 may collide with a filter (not shown),which is disposed under the base 210, thereby breaking the filter.Accordingly, in order to prevent breakage of the filter, there is a needto limit the distance by which the bobbin 110 moves downward. Thisfunction may be fulfilled by the fifth protrusion 451 of the fifthstopper 450.

It may be ideal in terms of handshake correction for the bobbin 110 tobe fitted into the housing 140 and moves in the second or thirddirection together with the housing 140. However, since the bobbin 110moves in the housing 140 in the first direction, a spacing distance w1may be present between the outer surface of the bobbin 110 and the innersurface of the housing 140.

Owing to presence of the spacing distance w1, the bobbin 110 may move inthe housing 140 in the second or third direction, thereby inhibiting theprecise handshake correction function of the lens moving apparatus.

Accordingly, by virtue of above-described configuration, the sixthprotrusion 452 may limit the distance by which the bobbin 110 moves inthe housing 140 in the second or third direction so as to fulfill theprecise handshake correction function of the lens moving apparatus.

The fifth stoppers 450 may include a plurality of stoppers, which aresymmetrically disposed around the center of the bobbin 110.

When the lens moving apparatus performs the autofocusing or handshakecorrection function, it may be preferable for the bobbin 110 to move inthe first, second or third direction and for the fifth stoppers 450 tobe symmetrically disposed as described above so as to enable the bobbin110 to move by uniform distances in the first, second and thirddirections.

FIG. 7 is a bottom perspective view showing the housing 140 according toan embodiment. FIG. 8 is a perspective view showing part of the lensmoving apparatus according to the embodiment. FIG. 9 is a side viewshowing part of the lens moving apparatus according to the embodiment.FIG. 10 is an enlarged view showing region A of FIG. 9.

The lens moving apparatus according to the embodiment may include sixthstoppers 460. As shown in FIGS. 7 to 10, the sixth stoppers 460 may beformed on the housing 140. The sixth stoppers 460 may protrude downwardfrom the lower surface of the housing 140.

The sixth stoppers 460 may be provided, for example, on the corners ofthe housing 140. The sixth stoppers 460 may include a plurality ofstoppers, which are symmetrically disposed around the center of thehousing 140.

In order to limit the distance by which the housing 140 can movedownward while keeping the housing 140 in the state of not beinginclined in the second or third direction, perpendicular to the firstdirection, the sixth stoppers 460 may be preferably disposed in thesymmetrical fashion described above.

When the sixth stoppers 460 are disposed on the corners of the housing140, the lower surfaces of the sixth stoppers 460 may contact the areaof the circuit member 231 at which the second coils 230 are not formedso as to prevent the second coils 230 from being broken due to collisionbetween the sixth stoppers 460 and the second coils 230.

As described above, unlike the bobbin 110, the housing 140 may notactively move upward and downward in the first direction. However, sincethe lower ends of the first magnets 130 and the upper end of the secondcoils 230 are positioned to face each other with a spacing distance w1therebetween, as shown in FIG. 10, when the support members 220 arewarped due to external impact, the spacing distance w1 defines a space,thereby allowing the housing 140 to move downward in the firstdirection.

When the lens moving apparatus performs the handshake correctionfunction, the housing 140 may be inclined in the second or thirddirection, whereby the housing 140 may move downward in the firstdirection.

As the housing 140 moves downward, the support members 220 may beextended in the length direction by being subjected to tensile force orbending moment. When excessive downward movement of the housing 140 isrepeated, the support members 220 are extended so far that deformationof the support members 220 exceeds the elastic limit, whereby thesupport members 220 may be damaged, even breaking in severe cases.

Accordingly, the sixth stoppers 460 may limit the distance by which thehousing 140 moves upward in order to prevent damage, breakage or thelike of the support members 220.

When the housing 140 excessively moves downward, the bobbin 110 fittedin the housing may also move downward. When the bobbin 110 moves too fardownward, the lower end of the lens barrel, which is coupled to thebobbin 110 may collide with a filter, which may be disposed under thebase 210, thereby breaking the filter.

Accordingly, in order to prevent breakage of the filter, there is a needto limit the distance by which the housing 140 and the bobbin 110 movedownward. This function may be fulfilled by both the fifth stoppers 450and the sixth stoppers 460.

The sixth stoppers 460 may serve to prevent the lower surfaces of thefirst magnets 130 from contacting the upper surfaces of the second coils230. As shown in FIGS. 8 to 10, in the lens moving apparatus accordingto the embodiment, the lower ends of the first magnets 130 may bedisposed to face the second coils 230.

Accordingly, when the housing 140 moves too far downward, the firstmagnets 130 may directly collide with the second coils 230, therebydamaging or breaking the second coils 230. For this reason, the sixthstoppers 460 may limit the distance by which the housing 140 movesdownward such that the first magnets 130 do not directly contact thesecond coils 230. As a result, it is possible to prevent damage orbreakage of the second coils 230 caused by the impact of the firstmagnets 130.

To this end, the lower surfaces of the first magnets 130 and the uppersurfaces of the second coils 230 are disposed to be spaced apart fromeach other, and the lower ends of the sixth stoppers 460 may bepositioned lower than the lower surfaces of the first magnets 130 in thefirst direction.

Specifically, it is preferable that the spacing distance w1 between thelower surfaces of the first magnets 130 and the upper surfaces of thesecond coils 230 be longer than the second distance w2, which ismeasured from the upper surfaces of the second coils 230 to the lowerends of the sixth stoppers 460 in the first direction.

In other words, since the second distance w2 is designed to be smallerthan the spacing distance w1, even when the housing 140 moves downward,the lower ends of the sixth stoppers 460 first contact the uppersurfaces of the second coils 230, thereby preventing the lower ends ofthe first magnets 130 from directly contacting the second coils 230 andpreventing the impact from being applied to the second coils 230.

In the lens moving apparatus according to the embodiment, the spacingdistance w1 may be set to be within a range of 0.04 mm to 0.26 mm in thenormal state in which the support members 220 are not deformed bybending, stretching or compression. More preferably, the spacingdistance w1 may be set to be within a range of 0.08 mm to 0.13 mm.

The first to sixth stoppers, which have been described in the aboveembodiment, may be independently provided in the lens moving apparatus.In other words, the lens moving apparatus according to the embodimentmay include one or more of the first to sixth stoppers.

In the embodiment, the respective stoppers, which are provided in thelens moving apparatus, have effects of being able to prevent damage orbreakage of the support members 220 due to deformation thereof and beingable to prevent damage or breakage of the second coils 230 due toimpact.

Furthermore, when mechanical resonance is generated by the supportmembers 220, some of the stoppers have an effect of making it possibleto easily control resonance frequency.

In addition, some of the stoppers have an effect of being able toprevent breakage of the filter, provided under the base 210, due toimpact.

The lens moving apparatus according to the embodiment may beincorporated in devices in various fields, for example, a camera module.Such a camera module may be applied to mobile devices such as cellularphones.

The camera module according to the embodiment may include the lensbarrel coupled to the bobbin 110, an image sensor (not shown), a printedcircuit board, and an optical system.

The lens barrel may be constructed as described above, and the printedcircuit board may constitute the bottom surface of the camera module onwhich the image sensor is mounted.

The optical system may include at least one lens for transmitting imagesto the image sensor. The optical system may be provided with an actuatormodule capable of fulfilling autofocusing and handshake correctionfunctions. The actuator module for fulfilling the autofocusing functionmay be constructed in various fashions, and mainly adopts a voice coilunit motor. The lens moving apparatus according to the above-describedembodiment may serve as an actuator module for fulfilling bothautofocusing and handshake correction functions.

Although not shown in the drawings, the camera module may furtherinclude an infrared-screening filter. The infrared-screening filterserves to shield the image sensor from light in an infrared range. Thebase 210 shown in FIG. 2 may include the infrared-screening filtermounted at a position corresponding to the image sensor, and may becoupled to a holder member (not shown). The base 210 may support thelower portion of the holder member.

The base 210 may be provided with an additional terminal member forconnection with the printed circuit board 250, and the terminal membermay also be integrally formed using a surface electrode. The base 210may serve as a sensor holder for protecting the image sensor. In thiscase, although the base 210 may be provided along the lateral sidesurface thereof with protrusions that project downward, these are notessential components. Although not shown in the drawings, an additionalsensor holder disposed under the base 210 may fulfill the same functionas the protrusions.

FIG. 11 is a perspective view schematically showing the lens movingapparatus according to another embodiment. FIG. 12 is an explodedperspective view showing the lens moving apparatus according to theembodiment.

As shown in FIG. 12, the lens moving apparatus according to theembodiment may include a movable unit. The movable unit may fulfill theautofocusing function of the lens. The movable unit may include a bobbin1100, a first coil 1200, first magnets 1300, a housing 1400, an upperelastic member 1500, a lower elastic member 1600, a position detectionsensor 1700 and a second magnet 1800.

The bobbin 1100 may be provided on the outer surface thereof with thefirst coil 1200 disposed between the first magnets 1300. Byelectromagnetic interaction between the first magnets 1300 and the firstcoil 1200, the bobbin 1100 may reciprocate in the first direction in thespace inside the housing 1400.

The bobbin 1100 may be provided on the outer surface thereof with thefirst coil 1200 so as to electromagnetically interact with the firstmagnets 1300.

As shown in FIG. 12, according to the embodiment, the first coil 1200includes two coils, which are wound around two areas on the outersurface of the bobbin 1100. In other words, the first coil 1200 mayinclude a plurality of coils, which are wound around a plurality ofareas of the outer surface of the bobbin 1100, whereby the first coils,wound around the plurality of areas, are spaced apart from each other inthe first direction.

Each of the first magnets 1300, which are disposed to correspond to thefirst coil 1200, may include a plurality of magnets in which the N poleand the S pole are disposed side by side, both in the first directionand in the direction perpendicular to the first direction.

Although not shown in the drawings, each of the first magnets 1300 maybe configured such that the N pole and the S pole are disposed side byside, only in the first direction, or in a direction perpendicular tothe first direction.

The bobbin 1100 may move in the first direction in the state of beingelastically supported by the upper elastic member 1500 and the lowerelastic member 1600 in order to fulfill the autofocusing function.

The housing 1400 may be configured to have an approximately rectangularhollow column shape for supporting the first magnets 1300. The firstmagnets 1300 may be coupled to the housing 1400. As described above, thebobbin 1100 may be disposed on the inner surface of the housing 1400,and may be supported by the housing 1400 in the state of being capableof moving in the first direction.

The housing 1400 may have four side flat walls. The surface area of eachof the side walls of the housing 1400 may be equal to or greater thanthat of each of the first magnets 1300. Among the four side walls, twoside walls that face each other may be provided with respective magnetfitting holes or recesses into which the first magnets 1300 are fitted.

As shown in FIG. 12, each of the side walls of the housing 1400 may beprovided with two first magnets 1300, which are arranged vertically.Accordingly, the magnet fitting holes or recesses in the housing 1400may be provided in a number corresponding to the number of first magnets1300.

The pair of first magnets 1300 may be disposed so as to be symmetricalto the center of the housing 1400.

If the first magnets 1300 are asymmetrically disposed with respect tothe center of the housing 1400 so as to face each other and aredeflected to one side of the housing 140, electromagnetic force is notcorrectly applied to the coil 1200 of the bobbin 1100, but is appliedtoward the one side, whereby the bobbin 1100 may be tilted.

Accordingly, the pair of first magnets 1300 is preferably disposed so asto be symmetrical around the center of the housing 1400.

One of the two remaining side walls of the housing 1400, other than thetwo side walls containing the first magnets 1300, may be provided with asensor through hole into which the position detection sensor 1700, whichis to be described later, is fitted.

Accordingly, among the four side walls of the housing 1400, two sidewalls that face each other may be provided with respective first magnets1300, and one of the two remaining side walls, other than the two sidewalls containing the first magnets 1300, may be provided with theposition detection sensor 1700.

The upper elastic member 1500 and the lower elastic member 1600 may becoupled to the bobbin 1100 and the housing 1400, respectively, and maybe disposed on the bobbin 1100 and under the housing 1400, respectively.

The upper elastic member 1500 and the lower elastic member 1600 mayelastically support the upward and/or downward movement of the bobbin1100 in the first direction. The upper elastic member 1500 and the lowerelastic member 1600 may be constituted by leaf springs.

As shown in FIG. 12, the lower elastic member 1600 may be composed oftwo separated elastic member parts. By virtue of the separated structureof the lower elastic member 1600, current of different polarities ordifferent electric powers may be applied to the respective elasticmember parts of the lower elastic member 1600.

In a modification, the upper elastic member 1500 may be composed of twoseparated elastic member parts whereas the lower elastic member 1600 maybe integrally constructed.

The upper elastic member 1500, the lower elastic member 1600, the bobbin1100 and the housing 1400 may be assembled with one another through abonding process using thermal fusion and/or an adhesive. Here, theassembly may be implemented through bonding using an adhesive afterthermal fusion.

The position detection sensor 1700 may constitute a displacementdetection unit for determining the displacement values of the bobbin1100 in the first direction, in conjunction with the second magnet 1800,described later. To this end, the position detection sensor 1700 and thesensor fitting through hole may be disposed at a position correspondingto the position of the second magnet 1800.

The second magnet 1800 may be coupled to the bobbin 1100. Accordingly,when the bobbin 1100 moves in the first direction, the second magnet1800 may be displaced the same distance as the bobbin 1100.

The second magnet 1800 may be integrally constructed, and may bedisposed such that the N pole thereof is positioned at an upper part ofthe bobbin 1100 and the S pole thereof is positioned at a lower part ofthe bobbin 1100. However, the disposition of the second magnet 1100 isnot limited thereto, and the opposite disposition of the N and S polesis also possible.

The second magnet 1800 may be constituted by a single magnet, or by twoor more magnets which are integrally coupled to each other. The specificstructure of the second magnet 1800 will be described later withreference to FIGS. 14B and 14C.

The second magnet 1800 may be divided into two sections with respect tothe plane perpendicular to the optical axis. The second magnet 1800 maybe spaced apart from the position detection sensor 1700 by apredetermined distance in a direction perpendicular to the firstdirection.

The base 2100 may be disposed under the bobbin 1100, and may beconfigured to have an approximately rectangular shape. The printedcircuit board 2500 and the lower elastic member 1600 may be mounted onthe base 2100.

The cover member 3000 may be coupled to the upper portion of the base2100. Specifically, the base 2100 and the cover member 3000 may besealingly secured to each other by an adhesive or the like applied tomating ends thereof that contact each other.

The printed circuit board 2500 may be coupled to one side surface of thehousing 1400. The printed circuit board 2500 may be provided with aterminal member 2530.

The terminal member 2530 may be provided with a plurality of terminals2510 in order to receive external power and supply the current to thecoil 1200 of the bobbin 1100 and the position detection sensor 1700. Thenumber of terminals 251 provided on the printed circuit board 2500 maybe increased or decreased depending on the kinds of components to becontrolled. According to the embodiment, the printed circuit board 2500may be embodied as a flexible printed circuit board (FPCB).

The printed circuit board 2500 may include a controller, which furthercontrols the amount of current applied to the coil 1200 based on thedisplacement value detected by the displacement detection unit.

In other words, the controller may be mounted on the printed circuitboard 2500. In another embodiment, the controller may not be mounted onthe printed circuit board 2500, but may be mounted on another board. Theadditional board may be a board on which the image sensor of the cameramodule is mounted, or may be another additional board.

The cover member 3000 may be configured to have an approximatelyrectangular box shape. The cover member 3000 may accommodate the movableunit, a portion of the printed circuit board 2500 and the like, and maybe coupled to the base 2100.

The cover member 3000 may protect the movable unit, the printed circuitboard 2500 and the like, accommodated therein, and may particularlyprevent the electromagnetic field, generated by the first magnets 1300,the first coil 1200 and the like, accommodated therein, from leaking tothe outside, thereby focusing the electromagnetic field.

FIG. 13 is a perspective view showing the lens moving apparatusaccording to an embodiment, in which the coil 1200 is coupled to thebobbin 1100. As shown in FIG. 13, in the embodiment, the coil 1200 mayincludes a plurality of coils, which are wound around the outer surfaceof the bobbin 1100 and are spaced apart from each other in the firstdirection. FIG. 13 shows an embodiment in which the coil 1200 includestwo coils, which are wound around two parts of the outer surface of thebobbin 1100, which are spaced apart from each other in the firstdirection.

In order to maintain the spacing between each of the plurality of coils1200 at a constant value and keep the coils 1200 wound around the outersurface of the bobbin 1100 in a stable state, the bobbin 1100 may beprovided on the outer surface thereof with a spacer 1110.

As shown in FIG. 13, the spacer 1110 may be circumferentially formedaround the middle area of the outer surface of the bobbin 1100, and maybe configured to have a constant width when measured in the firstdirection. The width of the spacer 1110 in the first direction may bethe spacing between the plurality of coils 1200 in the first direction.

The spacer 1110 may be circumferentially formed around the outer surfaceof the bobbin 1100, and may be integrally formed so as to protrudeoutward from the bobbin 1100. As described above, the spacer 1110 mayserve to space the plurality of coils 1200 apart from each other at aconstant spacing in the first direction.

As shown in FIG. 12, since the coils 1200 include a plurality of coilsdisposed on a plurality of areas of the outer surface of the bobbin1100, each of the first magnets 1300, which correspond to the coils1200, may be constituted by a plurality of magnets, or may beconstituted by a single magnet which is magnetized at a plurality ofsections so as to correspond to the plurality of coils 1200.

The plurality of coils 1200 may be wound around the outer surface of thebobbin 1100 in opposite directions. In order to increase the magneticforce of the first magnets 1300, the first magnets 1300, which areprovided so as to face respective coils 1200, are preferably disposedsuch that unlike poles are allocated to the opposite surfaces ofadjacent first magnets that face each other in the first direction.

The reason for this is because there is a need to make the directions inwhich current flows through the plurality of coils 1200 different inorder to cause the directions of forces generated by the coils 1200 andthe first magnets 1300 to be the same, in accordance with Fleming'sleft-hand rule.

To this end, for example, the upper coil of the plurality of coils 1200may be wound clockwise around the outer surface of the bobbin 1100 whenviewed in the first direction, whereas the lower coil may be woundcounterclockwise around the outer surface of the bobbin 1100 when viewedin the first direction.

In contrast, the upper coil of the plurality of coils 1200 may be woundcounterclockwise and the lower coil may be wound clockwise around theouter surface of the bobbin 1100 when viewed in the first direction.

FIG. 14A is a perspective view showing the lens moving apparatusaccording to an embodiment, in which the second magnet 1800 is coupledto the bobbin 1100.

As described above, the second magnet 1800 and the position detectionsensor 1700, which is disposed to face the second magnet 1800, maycollectively constitute the displacement detection unit for detectingthe displacement value of the bobbin 1100 in the first direction.

In the embodiment, the second magnet 1800 may be provided at the bobbin1100. To this end, the bobbin 1100 may be provided on a side surfacethereof with a magnet mount 1130, on which the second magnet 1800 issecurely mounted.

As shown in FIG. 14A, the magnet mount 1130 may be configured to have asize and shape such that the second magnet 1800 is securely mounted onthe side surface of the bobbin 1100. For example, the magnet mount 1130may be configured to have a recessed shape, which is formed in a portionof the side surface of the bobbin 1100.

The second magnet 1800 may be mounted on the magnet mount 1130, and maythen be secured to the bobbin by means of an adhesive or the like. Owingto the presence of the magnet mount 1130, the spacer 1110 is cut andinterrupted at the area at which the magnet mount 1130 is formed.

Accordingly, even when the coils 1200 are wound around the outer surfaceof the bobbin 1100, the second magnet 1800 may have a non-coil area,which is positioned at the interrupted area of the spacer 1110 and has asize corresponding to the spacing between the plurality of coils 1200.

As a result, the magnet 1800 secured to the bobbin 1100 may be disposedat the side surface of the bobbin 1100 that is opposite the positiondetection sensor 1700 so as to directly face the position detectionsensor 1700 through the non-coil area. Furthermore, the second magnet1800 may be disposed to face the detecting portion of the positiondetection sensor 1700.

As described above, by providing the non-coil area between the secondmagnet 1800 and the position detection sensor 1700, at which the coil1200 is not present, the second magnet 1800 may directly face theposition detection sensor 1700 without interference with the coils 1200.Consequently, it is possible to reduce detection error by the positiondetection sensor 1700, which is caused by interference with currentflowing through the coils 1200.

FIG. 14B is front view showing the magnetized structure of the secondmagnet 1800 according to an embodiment. FIG. 14C is a front view showingthe magnetized structure of the second magnet 1800 according to anotherembodiment.

As shown in FIG. 14B, the second magnet 1800 according to an embodimentmay be constituted by a single magnet, and may be disposed such that theN pole and the S pole are arranged in the first direction.

In this case, the second magnet 1800 may be disposed such that the Npole is positioned higher than the S pole or such that the S pole ispositioned higher than the N pole.

As shown in FIG. 14C, the second magnet 1800 may be constituted by twosecond magnets 1800-1 and 1800-2, each of which is configured as shownin FIG. 14B and which are integrally coupled to each other such thatfour magnetic poles, that is, two N poles and two S poles, are provided,and such that the N pole and the S pole of each magnet are arranged inthe first direction.

The second magnets 1800-1 and 1800-2 may be disposed in such a fashionthat the poles that are adjacent to each other in the first direction,are different from each other.

Specifically, in the second magnet 1800-1, which is positioned on theright side in the drawing, the N pole is positioned higher than the Spole. In the second magnet 1800-2, which is positioned on the left sidein the drawing, the S pole is positioned higher than the N pole.

In contrast, in the second magnet 1800-1, which is positioned on theright side in the drawing, the S pole is positioned higher than the Npole. In the second magnet 1800-2, which is positioned on the left sidein the drawing, the N pole is positioned higher than the S pole.

FIG. 15 is a side view showing the disposition of the bobbin 1100, theposition detection sensor 1700 and the second magnet 1800 in the lensmoving apparatus according to an embodiment.

The second magnet 1800 is mounted on the side surface of the bobbin1100, and the position detection sensor 1700 is mounted on the housing1400 so as to face the second magnet 1800.

As the bobbin 1100 moves in the first direction, the second magnet 1800moves in the first direction together with the bobbin 1100, and theposition detection sensor 1700, mounted on the housing 1400, may detectdisplacement values of the second magnet 1800 and the bobbin 1100 in thefirst direction by detecting variation in magnetic force generated bymovement of the second magnet 1800 in the first direction.

Since the coil 1200 is disposed between the second magnet 1800 and theposition detection sensor 1700, opposite surfaces of the second magnet1800 and the position detection sensor 1700 that face each other may bespaced apart from each other by a predetermined distance in a directionperpendicular to the first direction.

FIG. 16 is a side view showing the disposition of the bobbin 1100, theposition detection sensor 1700, the second magnet 1800 and the coils1200 in the lens moving apparatus according to the embodiment.

As described above, the coil 1200 includes a plurality of coils woundaround a plurality of areas on the outer surface of the bobbin 1100 soas to provide an upper coil 1200 and a lower coil 1200. The upper coil1200 and the lower coil 1200 are disposed so as to have a predeterminedspacing in the first direction by means of the spacer 1110. The uppercoil 1200 and the lower coil 1200 may be wound in opposite directions.

The position detection sensor 1700 may be disposed such that at least aportion of the surface of the position detection sensor 1700, whichfaces the second magnet 1800, is positioned at the gap between theplurality of coils 1200 so as to directly face the second magnet 1800.

In other words, although the coil 1200 is wound around the outer surfaceof the bobbin 1100, the second magnet 1800 may have a non-coil volume,in which the coil 1200 is not present, that is, the space obtained bythe spacing between the upper coil 1200 and the lower coil 1200,multiplied by the thickness of the second magnet 1800 in the directionperpendicular to the first direction.

Accordingly, by providing the non-coil area, in which the coils 1200 arenot present, between the second magnet 1800 and the position detectionsensor 1700, the second magnet 1800 may directly face the positiondetection sensor 1700 without interference with the coils 1200.

If the coils 1200 are disposed between the second magnet 1800 and theposition detection sensor 1700, an interference phenomenon, in which thecurrent through the coils 1200 distorts the structure or intensity ofthe magnetic field generated by the second magnet 1800, may occur.

Due to the interference phenomenon, when the second magnet 1800 moves inthe first direction, the position detection sensor 1700 detects amagnetic field that is distorted by the current flowing through thecoils 1200, rather than the correct magnetic field generated by thesecond magnet 1800.

For this reason, detection error occurs at the position detection sensor1700, and thus the position detection sensor 1700 is not able toprecisely detect the displacement value of the second magnet 1800 in thefirst direction.

According to the embodiment, by providing the non-coil area between thesecond magnet 1800 and the position detection sensor 1700 as describedabove, it is possible to mitigate the interference phenomenon caused bycurrent flowing through the coils 1200.

Consequently, it is possible to remarkably reduce the detection error ofthe position detection sensor 1700 in detecting the displacement valueof the second magnet 1800 in the first direction due to the interferencephenomenon.

FIG. 17 is a graph representing the results of experimentation on thedrive characteristics of the lens moving apparatus according to anembodiment. In the graph, GAIN may be converted into a displacementvalue of the second magnet 1800 in the first direction throughappropriate conversion from the value detected by the position detectionsensor 1700.

In the graph, the gain of the lens moving apparatus according to theembodiment, which is provided with the non-coil area, is denoted by L1,and the gain of a lens moving apparatus that is not provided with thenon-coil area because only one coil 1200 is wound around the outersurface of the bobbin 1100, is denoted by L2.

In the graph, PHASE may be represented by the phase difference between acurrent input value of the coil 1200 and a current output value of theposition detection sensor 1700, and the phase is denoted by L3.

Since the displacement value of the second magnet 1800 in the firstdirection and the displacement value of the bobbin 1100 in the firstdirection are identical to each other, detection error by the positiondetection sensor 1700 may decrease further as L1 or L2 becomesapproaches with L3.

From area B in the graph, it is noted that L3 is continuously lowered asthe frequency is increased. However, it is also noted that curve L1 orL2 has a rising section in the B area.

Comparing curve L1 with curve L2 in the area B, as the frequency isincreased, the gain of curve L1 is increased to a large extent comparedto curve L3, and the rate of increase of curve L1 is constant.

Although the gain of L2 is increased more than that of curve L3 with anincrease in frequency, the rate of increase of curve L2 is notably lowerthan that of curve L 1. When the frequency is further increased afterthe increase of the gain, the gain is decreased.

Comparing curve L1 with curve L2, the pattern of variation of curve L2is more similar to that of curve L3 than to that of L1. This shows thatthe detection error by the position detection sensor 1700, attributableto current flowing through the coil 1200 in the lens moving apparatusequipped with the non-coil area, is less than in a lens moving apparatusnot equipped with the non-coil area.

The error in the detection of the displacement value by the positiondetection sensor 1700 in the first direction of the lens movingapparatus according to the embodiment, which is caused by the differencebetween the gain and the phase representing the current input value ofthe coils 1200, may be dramatically reduced or eliminated throughcalibration.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

What is claimed is:
 1. A lens moving apparatus comprising: a bobbinadapted to move upward and downward in a first direction; a housing inwhich the bobbin is accommodated and which is movable upward anddownward in the first direction; a cover member accommodating the bobbinand the housing; and a base to which a lower portion of the cover memberis coupled, wherein the cover member has an opening formed in an upperface thereof, and is provided at an area thereof surrounding the openingwith a first stopper for limiting a distance by which the bobbin movesupward.
 2. The lens moving apparatus according to claim 1, wherein thefirst stopper is formed by depressing an outer surface of an upper wallof the cover member downward and protruding a lower surface of the upperwall of the cover member downward.
 3. The lens moving apparatusaccording to claim 1, wherein the cover member includes a second stopperformed near a side of an upper surface of the cover member so as tolimit a distance by which the housing moves upward.
 4. The lens movingapparatus according to claim 1, wherein the cover member includes athird stopper formed at a side surface thereof so as to limit a distanceby which the housing moves in a second or third direction.
 5. The lensmoving apparatus according to claim 4, wherein the housing includes afirst protrusion formed on a side surface thereof so as to face thethird stopper.
 6. The lens moving apparatus according to claim 4,wherein the third stopper is formed by depressing an outer surface of aside wall of the cover member inward and protruding a lower surface ofthe side wall of the cover member inward.
 7. The lens moving apparatusaccording to claim 1, wherein the bobbin includes a fourth stopperprotruding from an outer surface thereof so as to limit a distance bywhich the bobbin moves downward.
 8. The lens moving apparatus accordingto claim 7, wherein the fourth stopper comprises: a second protrusion,which is disposed such that a lower surface thereof faces a firststepped portion, which is formed on the housing so as to limit adistance by which the bobbin moves downward; and a third protrusion,which protrudes upward from the second protrusion and partially contactsan inner surface of the housing so as to guide movement of the bobbin inthe first direction together with the housing.
 9. A lens movingapparatus comprising: a bobbin adapted to move upward and downward in afirst direction; a housing in which the bobbin is accommodated and ismovable upward and downward in the first direction; a cover memberaccommodating the bobbin and the housing; and a base to which a lowerportion of the cover member is coupled, wherein the bobbin includes afifth stopper, which protrudes downward from a lower portion of thebobbin to limit a distance by which the bobbin moves downward in asecond or third direction.
 10. The lens moving apparatus according toclaim 9, wherein the base includes a fourth protrusion protrudingupward, wherein the fifth stopper comprises: a fifth protrusion, whichis positioned such that a portion of a lower surface thereof faces thefourth protrusion and contacts an upper surface of the fourth protrusionto limit a distance by which the bobbin moves downward; and a sixthprotrusion, which protrudes downward from the fifth protrusion andcontacts, at a portion thereof an inner surface of the fourth protrusionto limit a distance by which the bobbin moves in the second or thirddirection.
 11. A lens moving apparatus comprising: a first magnet; ahousing on which the first magnet is mounted; a bobbin on an outersurface of which a coil is wound; a second magnet mounted on the bobbin;and a position detection sensor disposed to face the second magnet,wherein the coil includes a plurality of coils, which are wound around aplurality of areas of an outer surface of the bobbin and are spacedapart from each other in the first direction, and the position detectionsensor is disposed at at least a portion thereof between the pluralityof coils.
 12. The lens moving apparatus according to claim 11, whereinthe first magnet is constructed to face the plurality of coils.
 13. Thelens moving apparatus according to claim 11, wherein the plurality ofcoils are wound around the outer surface of the bobbin in differentdirections.
 14. The lens moving apparatus according to claim 13, whereinthe second magnet is positioned such that an N pole and an S pole arearranged in the first direction.
 15. The lens moving apparatus accordingto claim 13, wherein the bobbin includes a spacer formed on an outersurface thereof so as to space the plurality of coils apart from eachother in the first direction.
 16. The lens moving apparatus according toclaim 15, wherein the spacer is formed around a middle area of an outersurface of the bobbin and has a width which is constant in the firstdirection.
 17. The lens moving apparatus according to claim 11, whereinthe position detection sensor is positioned at at least a portion of asurface thereof facing the second magnet in a gap defined between theplurality of coils.
 18. The lens moving apparatus according to claim 11,wherein the bobbin includes a magnet mount, which is formed on a sidesurface of the bobbin and on which the second magnet is securelymounted.
 19. The lens moving apparatus according to claim 11, whereinthe first magnet includes a pair of magnets, and wherein the housing isprovided at opposite side surfaces thereof with the pair of firstmagnets, and is provided with the position detection sensor at remainingside surfaces thereof, other than the opposite side surfaces on whichthe pair of first magnets are mounted.
 20. The lens moving apparatusaccording to claim 11, further comprising: a printed circuit boardmounted on a side surface of the housing; and upper and lower elasticmembers respectively disposed on and under the bobbin and the housing.